Out‐of‐plane strength reduction of unreinforced masonry walls because of in‐plane damages

Dolatshahi, Kiarash M.; Yekrangnia, Mohammad

doi:10.1002/eqe.2574

Cited by 38 publications

(18 citation statements)

References 12 publications

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“…Another way of presenting IP-OP interaction for the models in this study is in the form of normalized OP strength versus IP drift ratio. These results for Model-1 and Model-2 together with the results proposed by Dolatshahi and Yekrangnia [25] are shown in Fig. 20.…”

Section: Results Discussionsupporting

confidence: 64%

“…It was shown that regardless of the aspect ratio and existence of vertical loads, the OP behavior of infilled frames is not noticeably affected by the IP displacement demand, provided that the displacement is smaller than the displacement related to IP ultimate strength. Unlike the unreinforced masonry walls in which they experience considerable reduction in the OP strength capacity even by applying a small IP displacement [24,25], masonry infill walls benefit from the positive effects of formation of IP diagonal compressive struts in improving the arching action as well as in increasing their OP strength capacity. This is an interesting finding in this study since it clearly proves that the IP and OP interaction for masonry infilled frames may not be much of concern and therefore, the available relations in the design codes for determination of the IP and OP strength capacity of infilled frames as independent behaviors can lead to accurate results.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of brick infill walls under in-plane and out-of-plane loading

Bahreini¹,

Mahdi²,

Najafizadeh³

2017

J. vibroeng.

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In this paper, the in-plane (IP) and out-of-plane (OP) interaction of masonry infill walls with various length-to-height ratios and vertical forces from dead and live loads are studied. For this purpose, calibrated numerical simulation for IP and OP behaviors of infilled frames has been exploited. In this method, first, the vertical loads are applied, then increasing IP displacement is imposed at the top of the models and finally OP demands are applied to the walls up to their failure. Two different methods of applying OP loading are studied: increasing static uniform pressure on the wall, and increasing dynamic acceleration. Three levels of IP displacement demands are considered: at the first reduction of tangential stiffness for IP force-displacement response, at the maximum IP strength, and at the displacement related to 20 % reduction of IP strength. The results obviously show that up to the point of the maximum IP strength capacity, the OP behavior of the considered models slightly enhanced due to the effects of improved arching actions originated from the development of IP compressive diagonal struts. Moreover, slight differences exist between the static and dynamic loadings in OP direction, hence proving the accuracy of the equivalent static loading in determining OP capacity for the studied infilled frames. Comparing the results of masonry infilled frames with those of the corresponding masonry walls indicate that the IP displacements negatively affect the OP strength in the latter, even at small IP displacement demands; however, the rate of OP strength reduction in larger IP drift ratios is lower compared to that of the corresponding infilled frame.

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Section: Results Discussionsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Evaluation of brick infill walls under in-plane and out-of-plane loading

Bahreini¹,

Mahdi²,

Najafizadeh³

2017

J. vibroeng.

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“…In slender façades, the dynamic interaction between in‐plane and out‐of‐plane movements tends to be scarce, because the in‐plane vibration modes correspond to periods that are usually much shorter than the flexural ones. On the other hand, a much more complex interaction between in‐plane and out‐of‐plane damage mechanisms can be expected in very different façade typologies, such as some baroque façades, which are not simply planar and often integrate heavy bell towers …”

Section: Discrete Models Of the Masonry Façadesmentioning

confidence: 99%

“…15,17 The main façades are on the left side of the drawings a much more complex interaction between in-plane and out-of-plane damage mechanisms can be expected in very different façade typologies, such as some baroque façades, which are not simply planar and often integrate heavy bell towers. [25][26][27][28] For the purposes of the present study, the numerical modelling should be efficient, to perform full nonlinear dynamic analyses with an acceptable computational effort, but not simplistic, since the damage response of the building materials, in the context of the composite nature of the 3-leaf masonry walls, should be properly included. [29][30][31][32] Special attention should be devoted to the definition of a reasonable nonlinear material response compatible with the experimental evidence as well as with analytical and microstructure numerical modelling, 16,33,34 by accounting for the static vertical compression, the 3-leaf bond effects, the internal friction, and the progression of damage with hysteretic dissipation.…”

Section: Out-of-plane Damage Mechanismsmentioning

confidence: 99%

A numerical study on the cumulative out‐of‐plane damage to church masonry façades due to a sequence of strong ground motions

Casolo

2017

Earthq Engng Struct Dyn

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Summary Seismic shocks occur sometimes as a sequence, close in space and time, of destructive events of comparable intensity. In these cases, a significant portion of the damage to historical buildings can be related with the cumulated damage on structures that become progressively more vulnerable. This research investigates the specific increase of damage determined by a sequence of strong ground motions, focusing the interest on the out‐of‐plane response of 2 church masonry façades. The dynamic analyses were performed by a specific rigid body and spring model RBSM, which only accounts for out‐of‐plane damage mechanisms. Two idealized models of façade, each made of 2 different masonry bonds, have been studied by applying various sequences of recorded accelerograms. The results highlighted a complex relationship between the spectral content of the seismic shocks and the characteristics of the structures that change in the course of the loading sequence due to the development of damage. The Housner spectral intensity proved to be a reliable scalar measure of the ground motion destructiveness for these façades. Moreover, when considering a design‐consistent accelerogram that causes a relevant damage pattern, ie, with a significant elongation of the effective first period of vibration, the numerical results indicated a possible spectral intensity threshold below which the occurrence of repeated seismic shocks, both before and after the reference design shock, can be considered as irrelevant. On the other hand, a catastrophic increase of damage should be expected when this threshold is overcome.

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“…Examination of the literature also reveals that most of the studies have focused on two‐dimensional behavior of URM walls. An extensive review by Dolatshahi of existing technical literature shows that there are few material models equipped to simulate the three‐dimensional behavior of URM walls . The authors have developed a three‐dimensional numerical procedure for modeling URM walls .…”

Section: Introductionmentioning

confidence: 99%

Multi‐directional response of unreinforced masonry walls: experimental and computational investigations

Dolatshahi

Aref

2016

Earthq Engng Struct Dyn

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SUMMARYThis paper describes the results of an experimental and numerical study that focused on multi-directional behavior of unreinforced masonry walls and established the requisite of the related proposed design equations. The tests were conducted following several sets of multi-directional loading combinations imposed on the top plane of the wall along with considering monotonic and cyclic quasi-static loading protocols. Various boundary conditions, representing possible wall-roof connections, were also considered for different walls to investigate the influence of rotation of the top plane of the wall on the failure modes. The results of the tests were recorded with a host of high precision data acquisition systems, showing three-dimensional displacements of a grid on the surface of the wall. Finite element models of the walls are developed using the commercial software package ABAQUS/Explicit compiled with a FORTRAN subroutine (VUMAT) written by the authors. The experimental results were then used to validate the finite element models and the developed userdefined material models. With the utility of validated models, a parametric study was performed on a set of parameters with dominant influence on the behavior of the wall system under in-plane and out-of-plane loading combinations. The experimental and numerical results are finally used to investigate the adequacy of ASCE 41 empirical equations, and some insights and recommendations are made.

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Out‐of‐plane strength reduction of unreinforced masonry walls because of in‐plane damages

Cited by 38 publications

References 12 publications

Evaluation of brick infill walls under in-plane and out-of-plane loading

Evaluation of brick infill walls under in-plane and out-of-plane loading

A numerical study on the cumulative out‐of‐plane damage to church masonry façades due to a sequence of strong ground motions

Multi‐directional response of unreinforced masonry walls: experimental and computational investigations

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